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authorChristoph Hellwig <hch@infradead.org>2008-11-28 14:23:31 +1100
committerNiv Sardi <xaiki@sgi.com>2008-12-01 11:06:44 +1100
commitbac8dca9f9b1dfcf9c4ecb4f9ca17185b828cc20 (patch)
treefa26840c5e85eeed63575615c140f2913e6d9189
parentb5a20aa2657063cbf3b47fc700603180de4bb554 (diff)
[XFS] fix NULL pointer dereference in xfs_log_force_umount
xfs_log_force_umount may be called very early during log recovery where If we fail a buffer read in xlog_recover_do_inode_trans we abort the mount. But at that point log recovery has started delayed writeback of inode buffers. As part of the aborted mount we try to flush out all delwri buffers, but at that point we have already freed the superblock, and set mp->m_sb_bp to NULL, and xfs_log_force_umount which gets called after the inode buffer writeback trips over it. Make xfs_log_force_umount a little more careful when accessing mp->m_sb_bp to avoid this. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Niv Sardi <xaiki@sgi.com>
-rw-r--r--fs/xfs/xfs_log.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 4bf44aef644c..8a5b05536a28 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -3569,7 +3569,8 @@ xfs_log_force_umount(
if (!log ||
log->l_flags & XLOG_ACTIVE_RECOVERY) {
mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
- XFS_BUF_DONE(mp->m_sb_bp);
+ if (mp->m_sb_bp)
+ XFS_BUF_DONE(mp->m_sb_bp);
return 0;
}
@@ -3590,7 +3591,9 @@ xfs_log_force_umount(
spin_lock(&log->l_icloglock);
spin_lock(&log->l_grant_lock);
mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
- XFS_BUF_DONE(mp->m_sb_bp);
+ if (mp->m_sb_bp)
+ XFS_BUF_DONE(mp->m_sb_bp);
+
/*
* This flag is sort of redundant because of the mount flag, but
* it's good to maintain the separation between the log and the rest